$dp = Hash.new 0
def f(n)
  $dp[[0,1]] = $dp[[0,2]] = $dp[[0,3]] = 1
  (1...n).each{|i|
    $dp[[i,1]] = ($dp[[i-2,2]] + $dp[[i-3,3]]) % M
    $dp[[i,2]] = ($dp[[i-1,1]] + $dp[[i-3,3]]) % M
    $dp[[i,3]] = ($dp[[i-1,1]] + $dp[[i-2,2]]) % M
  }
  ($dp[[n-1,1]] + $dp[[n-2,2]] + $dp[[n-3,3]]) % M
end

M = 10**9+7
N = gets.to_i
p f(N)